Sleep disturbances are related to glymphatic dysfunction in blepharospasm

Research has shown a close relationship between sleep and glymphatic function, with impaired glymphatic function potentially contributing to sleep problems in a bidirectional way. However, its role in sleep disturbances associated with dystonia remains unknown. This cross-sectional study aimed to investigate whether glymphatic function is impaired in dystonia and to explore its relationship with sleep disturbances. We conducted structural magnetic resonance imaging and diffusion tensor imaging (DTI) on two large cohorts: patients with blepharospasm (BSP, n = 45) and cervical dystonia (CD, n = 43), alongside age- and sex-matched healthy controls (HCs). Anxiety, depression, and sleep quality were evaluated using the Hamilton Anxiety Scale (HAMA), Hamilton Depression Scale (HAMD), and Pittsburgh Sleep Quality Index (PSQI), respectively. Analysis along the perivascular space (DTI-ALPS) index and choroid plexus volume (CPV) was used to assess glymphatic function in these participants. Patients with BSP and CD had higher HAMA, HAMD, and PSQI scores than those of HCs. Patients with BSP exhibited a lower DTI-ALPS index and larger CPV than those of HCs, while no significant differences were found between CD and HCs. In BSP and CD, PSQI scores positively correlated with HAMA and HAMD scores and negatively with the DTI-ALPS index in BSP. Multivariate analysis identified the DTI-ALPS index as a dependent predictive factor of the PSQI in patients with BSP. Our findings suggest that glymphatic function varies across types of focal dystonia, with glymphatic dysfunction potentially playing an important role in the pathogenesis of sleep disturbances in BSP.